The pre-crisis financial architecture was a system of mobile collateral. Safe debt, whether government bonds or privately produced bonds, ie asset-backed securities, could be traded, posted as collateral, and rehypothecated, moving to its highest value use. Since the financial crisis, regulatory...

In a financial system where balance sheets are continuously marked to market, asset price changes show up immediately in changes in net worth, and elicit responses from financial intermediaries, who adjust the size of their balance sheets. We document evidence that marked to market leverage is...